MES-acetate buffer recipe - (Feb/05/2012 )

I have a protocol which involves the use of "50mM MES-acetate, pH 6.0" buffer. I looked at the MES datasheet and there it is stated that the pKa of MES is 6.15 @ 20C. How can I titrate acetate into MES if the pH of MES is already ~6? Does anyone have a recipe for making MES-acetate pH6?

Thanks!

-liflaf1-

The pH of MES is not already 6.15. The pKa is 6.15, a huge difference. The pH of MES will be very high, and you have to mix it with acetic acid to get the pH down to 6.0. The pKa is the pH of a soluiton containing MES in which half of the MES is ionized, and half is un-ionized.